The present invention relates generally to fuel injectors for use in an internal combustion engine and, more particularly, to a valve seat retainer for securely attaching the valve seat into the fuel passage of the fuel injector.
It is well known in the automotive engine art to provide solenoid actuated fuel injectors for controlling the injection of fuel into the cylinders of an internal combustion engine. Fuel injectors generally include a body having internal and external components which are assembled together to provide an internal fuel passage for fuel flow therein. An injector valve is actuated within the fuel passage to control fuel flow, such that the injector valve axially separates from the a valve seat in an open position and sealingly engages the valve seat in a closed position.
In constructing the fuel injector, the valve seat and associated components are adjustably positioned in an outlet end of the fuel passage. A clamp load is then applied to the valve seat assembly and it is securely attached into the fuel passage of the injector. It is imperative that the magnitude and direction of the clamp load be accurately controlled in order to minimize distortion of the valve seat and to keep it precisely in position over the life of the fuel injector.
Two techniques are typically used to attached the valve seat into the fuel passage. First, a weld is placed between the valve seat and the inner surface of the fuel passage. However, the welding process introduces heat between the components which may distort them, thereby causing fuel leaks. Second, an extending flange portion of the injector body may be crimped over the end of the fuel passage, thereby securing the valve seat within the fuel passage of the injector. In this case, the crimped flange portion of the body applies the clamp load to the valve seat. Since the crimped flange portion may experience some spring back, the magnitude and direction of the clamp load is unknown.
Therefore, it is desirable to provide a valve seat retainer for securely attaching the valve seat into the fuel passage of the fuel injector, such that the magnitude and direction of the clamp load is accurately known and maintained over the life of the fuel injector. It is also desirable that the valve seat retainer be designed to flex under load in order to maintain the clamp load during and after the assembly process. The valve seat retainer may also serve as a fuel director retainer for securely attaching the fuel director to the valve seat.
In accordance with the present invention, a fuel injector is provided for use in an internal combustion engine. The fuel injector includes an injector body having an axially extending fuel passage for fuel flow therein, an injection valve movable in the passage for controlling fuel flow, a valve seat adjustably positioned into an outlet end of the fuel passage, and a valve seat retainer for applying an axial load onto the valve seat and securely attaching the valve seat into the fuel passage of the injector body.
For a more complete understanding of the invention, its objects and advantages, refer to the following specification and to the accompanying drawings.